Lumo driving standard

[Efini92]

Agree with this. There are no prizes for arriving early, however you *will* get the sack if you go around tripping TPWS grids left right and centre!

Timetables are such that it’s possible to run on time without driving unduly aggressively.

Or they’ll make you a manager.

 

[bramling]

Passenger comfort is also a factor.

There isn’t necessarily a correlation between using harsher rates of braking and an uncomfortable ride. You can, after all, have the slowest driver in the world who does constant on/off when braking (something I find maddening!), or who throws everything on for the final stop producing an awful jolt.

Interestingly, someone commented earlier in the thread about many Lumo drivers being ex T&W Metro. Being up here this week and having used the Metro a fair bit over the years, I wouldn’t say their style is particularly aggressive. In fact on the contrary - compared to something like London Underground their driving is pretty placid. With a fairly sparse service by metro standards there’s no real need to rush round, of course.

 

[niggill617@gma]

We don’t get trained in any depth on units of deceleration so there mustn’t be a requirement by TOCs and industry bodies to understand them to any great degree.

You hit the nail on the head.

 

[niggill617@gma]

What is the "white pages of the working manual for rail staff" supposed to refer to?

Why was the driver of the Loughborough incident unable to check and calculate the brake force required; schedule 5 requirement. In fact it could of been done by simple kinematic equation in combination with the data plates on the rolling stock. Or just slap in the face Newton's Second Law, which should set the alarms ringing. That RAIB report is utter nonsense and does not compute.

Is the document still referred to as the white pages?

 

[craigybagel]

We don’t get trained in any depth on units of deceleration so there mustn’t be a requirement by TOCs and industry bodies to understand them to any great degree.

More importantly, it's also not a requirement to understand them in other to actually drive a train.

 

[philthetube]

If train drivers needed to know this then so would all other drivers.

 

[GC class B1]

If train drivers needed to know this then so would all other drivers.

I question the view that all drivers don’t need to understand the principles of deceleration when you consider the number of rear end collisions that occur because car drivers and other road users don’t understand braking distances in different circumstances.
There are also a number of incidents including a SPAD which may have been avoided if the the driver concerned had appreciated that the brake performance of their train was either degraded or was not as would be expected for the maximum speed advised to the driver by their documentation. In the case of the SPAD the driver’s documents gave a much higher maximum speed than the brake force permitted. An understanding of the principles of deceleration may have highlighted the problems before the incident occurred.

 

[DoubleO]

The vast majority of rear end road traffic collisions are due to lack of concentration. And I'd like you to elaborate on how a scientific understanding of deceleration could/would prevent SPADs. A driver needs to know the braking characteristics of the traction he is driving, have awareness of railhead conditions, and be able to use those two pieces of information along with good route knowledge to make good judgements on braking points. None of the above requires a scientific understanding of the principles of deceleration.

 

[niggill617@gma]

So

More importantly, it's also not a requirement to understand them in other to actually drive a train.

The vast majority of rear end road traffic collisions are due to lack of concentration. And I'd like you to elaborate on how a scientific understanding of deceleration could/would prevent SPADs. A driver needs to know the braking characteristics of the traction he is driving, have awareness of railhead conditions, and be able to use those two pieces of information along with good route knowledge to make good judgements on braking points. None of the above requires a scientific understanding of the principles of deceleration.

The RAIB feel the need to illustrate the emergency braking rate calculation, and the benefit of using it, as per attachment.

The whole issue of physics understanding is now subject to 5 year review of TDLCR, in part at least inter alia. I have stated my case to the HSE and the ORR, with supporting evidence, so we will see what happens.

No sorry some road drivers tailgate as a matter of ignorance.

 

[GC class B1]

Whilst I understand that may rear end collisions on the road are the result of lack of concentration, observing traffic moving on high speed road will show you that many drivers drive too close to the vehicles in front. An important part of the understanding the principles of deceleration is understanding that stopping distances are not linear but are proportional to the square of the speed. As an example the stopping distance at 60MPH will be 4 times that at at 30MPH. I also suspect that car drivers don’t realise that the reaction time between seeing brakes lights in front and actually achieving full brake force could result in travelling about 10 - 20 metres at 60 MPH in addition to the distance to actually stop. I assume the two second rule is intended to allow for reaction time.
With regard to train driving, whilst I know that when the train brake system is performing to the design, the stopping distances will be as expected and will take account of reaction and brake build up time, However in the rare occasions when brake system becomes degraded or some other braking anomaly occurring, an understanding of what deceleration should occur, e.g. speed reduction for a particular brake application during the Running Brake Test, may help to identify a problem if the actual performance is not as it should be.

 

[DoubleO]

Whilst I understand that may rear end collisions on the road are the result of lack of concentration, observing traffic moving on high speed road will show you that many drivers drive too close to the vehicles in front. An important part of the understanding the principles of deceleration is understanding that stopping distances are not linear but are proportional to the square of the speed. As an example the stopping distance at 60MPH will be 4 times that at at 30MPH. I also suspect that car drivers don’t realise that the reaction time between seeing brakes lights in front and actually achieving full brake force could result in travelling about 10 - 20 metres at 60 MPH in addition to the distance to actually stop. I assume the two second rule is intended to allow for reaction time.
With regard to train driving, whilst I know that when the train brake system is performing to the design, the stopping distances will be as expected and will take account of reaction and brake build up time, However in the rare occasions when brake system becomes degraded or some other braking anomaly occurring, an understanding of what deceleration should occur, e.g. speed reduction for a particular brake application during the Running Brake Test, may help to identify a problem if the actual performance is not as it should be.

That's not an understanding of the scientific principles of deceleration. That's having knowledge and experience of your route and traction and recognising when something isn't normal. If I apply the usual amount of brake at the usual location and I'm not slowing down enough I'll react accordingly. Drivers driving too close to the car in front isn't because they don't have a scientific knowledge of deceleration, coefficients of friction or anything else. It's a combination of laziness, impatience, and bad habits. This is clearly a subject you have knowledge and passion about, but the fact that everyone on this thread (not to mention the entire railway industry) feel that it's not necessary knowledge for drivers should tell you something.

 

[niggill617@gma]

The vast majority of rear end road traffic collisions are due to lack of concentration. And I'd like you to elaborate on how a scientific understanding of deceleration could/would prevent SPADs. A driver needs to know the braking characteristics of the traction he is driving, have awareness of railhead conditions, and be able to use those two pieces of information along with good route knowledge to make good judgements on braking points. None of the above requires a scientific understanding of the principles of deceleration.

A driver of considerable experience selects full service and takes 60 seconds to slow by 6 mph. He then powers up to line speed and has a double spad. The initial braking should of taken around 14 seconds including freewheel. Therefore driveability failed as the primary method of control. Theory would of been the braces after the broken belt. Two parameters are better than one. Train driving is not about calculating your way around the network, intuition first. It says on the tin, general professional knowledge, not necessarily a procedure.

 

[PupCuff]

A driver of considerable experience selects full service and takes 60 seconds to slow by 6 mph. He then powers up to line speed and has a double spad. The initial braking should of taken around 14 seconds including freewheel. Therefore driveability failed as the primary method of control. Theory would of been the braces after the broken belt. Two parameters are better than one. Train driving is not about calculating your way around the network, intuition first. It says on the tin, general professional knowledge, not necessarily a procedure.

I'm unsure what the ability to calculate deceleration would help with in this scenario.

The Driver in that example has for whatever reason not identified that the braking of the train was insufficient. If they haven't identified the braking was insufficient, they are not going to identify the need to make a follow up deceleration calculation.

Is the proposal that the driver could have worked out the rate of deceleration from the initial running brake test and then calculated back from the stop signal to gauge a braking point from linespeed at the reduced braking performance? It would be much safer to run the train at a reduced speed until the cause of the poor brake could be determined and resolved.

 

[GC class B1]

I'm unsure what the ability to calculate deceleration would help with in this scenario.

The Driver in that example has for whatever reason not identified that the braking of the train was insufficient. If they haven't identified the braking was insufficient, they are not going to identify the need to make a follow up deceleration calculation.

Is the proposal that the driver could have worked out the rate of deceleration from the initial running brake test and then calculated back from the stop signal to gauge a braking point from linespeed at the reduced braking performance? It would be much safer to run the train at a reduced speed until the cause of the poor brake could be determined and resolved.

I am not a train driver, However I have studied reports of investigations into incidents where the brake performance of the train had become degraded or had been incorrectly assessed before the driver began to drive the train but the driver was not aware of this. My understanding of the purpose of a Running Brake Test is to confirm that brake performance is satisfactory for the maximum speed and will stop the train within the signalling distance. I think there are two different situations at play here as far as driving experience is concerned. Firstly, as I would expect and is made clear from posts on this topic, drivers are competent and fully aware of the normal braking performance of the train they are driving, when to apply the brake and what brake rate to apply in all circumstances. Secondly, the point that is being mentioned in the posts by niggill617@gma is that he believes that an understanding of the mechanics of train braking would better enable drivers to assess whether the brake performance of their train was acceptable (I.e. the required deceleration had been achieved) and the brake system had not become degraded. Identifying a decifiency before the need arose to made a brake application for a signal or station could prevent an incident. In the example quoted the train brake performance was significantly degraded, however the initial brake application did not appear to indicate this to the driver and a double SPAD occurred because the train brake force was inadequate. The suggestion is that had the driver realised this braking deficiency, he could have taken appropriate action before the SPAD occurred. Those of us who have been in this industry for a long time know that incidents usually occur when something unexpected or out of the ordinary occurs.

 

[PupCuff]

I am not a train driver, However I have studied reports of investigations into incidents where the brake performance of the train had become degraded or had been incorrectly assessed before the driver began to drive the train but the driver was not aware of this. My understanding of the purpose of a Running Brake Test is to confirm that brake performance is satisfactory for the maximum speed and will stop the train within the signalling distance. I think there are two different situations at play here as far as driving experience is concerned.

I would add to that the benefits of a running brake test include making sure that braking performance is in line with what would normally be expected, being a barometer of railhead adhesion levels in the area, and providing a practical 'feel' of the train's braking performance so as to allow for any adjustments.

Firstly, as I would expect and is made clear from posts on this topic, drivers are competent and fully aware of the normal braking performance of the train they are driving, when to apply the brake and what brake rate to apply in all circumstances.

You would certainly expect so, yes.

Secondly, the point that is being mentioned in the posts by niggill617@gma is that he believes that an understanding of the mechanics of train braking would better enable drivers to assess whether the brake performance of their train was acceptable (I.e. the required deceleration had been achieved) and the brake system had not become degraded. Identifying a decifiency before the need arose to made a brake application for a signal or station could prevent an incident. In the example quoted the train brake performance was significantly degraded, however the initial brake application did not appear to indicate this to the driver and a double SPAD occurred because the train brake force was inadequate. The suggestion is that had the driver realised this braking deficiency, he could have taken appropriate action before the SPAD occurred. Those of us who have been in this industry for a long time know that incidents usually occur when something unexpected or out of the ordinary occurs.

We've established in your point above that the Driver would be fully aware of the normal braking performance of the train they're driving, so to have a significantly degraded deceleration should be noticeable. The first question we ask is, after carrying out a running brake test and finding that it's taken you such a long time to lose such a small amount of speed, what was the Driver's next action? In the example provided, this was to accelerate towards linespeed. The key question which needs to be identified is - why? This is not a safe or appropriate response following a clearly underperforming brake application. You don't need to know the physics behind deceleration to know that if you've got the brake in full and you've lost 6mph over one minute something is badly wrong. If a brake is so badly deficient that you notice it, then you will have noticed it already. If it isn't badly deficient enough for you to notice, then you won't notice it and won't know to investigate further.

 

[beany]

60 double yellow 40 single 20 magnet for the red.
Got a tpws incident under my belt and don't want another one.Yes I may arrive a few seconds later than others and may even get a please explain a delay,but once I hit restrictive signals,the timetable goes out of the window.And my decent manager will back me every time.

 

[ComUtoR]

My understanding of the purpose of a Running Brake Test is to confirm that brake performance is satisfactory for the maximum speed and will stop the train within the signalling distance.

I don't believe this is the case. I think I'll have a look about today.

I pretty much never run my train at its maximum speed and due to the nature of working Metro, I don't run to linespeed either because I'm accelerating and then braking for the next station. I might touch linespeed but in the grand scheme of things I spend most of my time under it.

Considering that linespeed change. I don't carry out a brake test each time. So a quick running brake at 20mph to determine if I could safely stop at 20mph would be different to what's needed at 100mph.

With the obsession about calculating braking performance I think a significant factor has been omitted. Gravity will also have an effect. Braking on a gradient will be different if your going up or down a hill.

There is also factor or running brake tests for the prevailing conditions being almost worthless a few seconds later. If I carry out a running brake test at location X on a dry section of track then it rains 5 minutes later. Any braking I do will now be affected by the weather. Even in leaffall by the time you carry out your first running brake,. The next 100m down the line could be significantly different.

Knowing my train is braking at 6% still doesn't tell me if it's going to stop if I was going 10mph or 60mph

 

[GC class B1]

I don't believe this is the case. I think I'll have a look about today.

I pretty much never run my train at its maximum speed and due to the nature of working Metro, I don't run to linespeed either because I'm accelerating and then braking for the next station. I might touch linespeed but in the grand scheme of things I spend most of my time under it.

Considering that linespeed change. I don't carry out a brake test each time. So a quick running brake at 20mph to determine if I could safely stop at 20mph would be different to what's needed at 100mph.

With the obsession about calculating braking performance I think a significant factor has been omitted. Gravity will also have an effect. Braking on a gradient will be different if your going up or down a hill.

There is also factor or running brake tests for the prevailing conditions being almost worthless a few seconds later. If I carry out a running brake test at location X on a dry section of track then it rains 5 minutes later. Any braking I do will now be affected by the weather. Even in leaffall by the time you carry out your first running brake,. The next 100m down the line could be significantly different.

Knowing my train is braking at 6% still doesn't tell me if it's going to stop if I was going 10mph or 60mph

With regard to needing to carry out an RBT (Running Brake Test) at each line speed. An RBT carried out at say 60 MPH, will establish whether the selected deceleration rate has been achieved, subject to sufficient wheel/rail adhesion. If say Step 2 is selected and 6%g is achieved then subject to the required adhesion being available this will confirm that the stopping distances at each speed will be achieved. A further RBT will not be necessary at a different line speed. As far as adhesion is concerned I know this will vary at different locations and an RBT will not help to identify where low adhesion may occur.

 

[ComUtoR]

If say Step 2 is selected and 6%g is achieved then subject to the required adhesion being available this will confirm that the stopping distances at each speed will be achieved.

Only at that specific time and location.

As far as adhesion is concerned I know this will vary at different locations and an RBT will not help to identify where low adhesion may occur.

And adhesion will affect the stopping distance.

The danger here is that if you "confirm" that the stopping distance "will" be achieved then you are giving someone a false sense of security.

There are other variables that need to be considered when and where you stick the brake in.

 

[43066]

A further RBT will not be necessary at a different line speed. As far as adhesion is concerned I know this will vary at different locations and an RBT will not help to identify where low adhesion may occur.

Yes it will! Drivers will regularly do RBTs to confirm low adhesion if it is suspected.

== Doublepost prevention - post automatically merged: 29 May 2022 ==

Only at that specific time and location.

Exactly. This is why it isn’t (or shouldn’t) be something you only ever do once at the start of a journey and then forget about.

 

[DoubleO]

I would add to that the benefits of a running brake test include making sure that braking performance is in line with what would normally be expected, being a barometer of railhead adhesion levels in the area, and providing a practical 'feel' of the train's braking performance so as to allow for any adjustments.

You would certainly expect so, yes.

We've established in your point above that the Driver would be fully aware of the normal braking performance of the train they're driving, so to have a significantly degraded deceleration should be noticeable. The first question we ask is, after carrying out a running brake test and finding that it's taken you such a long time to lose such a small amount of speed, what was the Driver's next action? In the example provided, this was to accelerate towards linespeed. The key question which needs to be identified is - why? This is not a safe or appropriate response following a clearly underperforming brake application. You don't need to know the physics behind deceleration to know that if you've got the brake in full and you've lost 6mph over one minute something is badly wrong. If a brake is so badly deficient that you notice it, then you will have noticed it already. If it isn't badly deficient enough for you to notice, then you won't notice it and won't know to investigate further.

Spot on

== Doublepost prevention - post automatically merged: 29 May 2022 ==

Yes it will! Drivers will regularly do RBTs to confirm low adhesion if it is suspected.

== Doublepost prevention - post automatically merged: 29 May 2022 ==



Exactly. This is why it isn’t (or shouldn’t) be something you only ever do once at the start of a journey and then forget

 

[GC class B1]

In response to the posts above, ii appears that I have not explained my point regarding degraded brake system performance correctly. In order to comply with the signalling and station stopping distances, two factors must apply. Firstly the brake system must achieve the demanded deceleration rate and secondly the wheel/rail adhesion (with the assistance of sanding and effective WSP operation where necessary) must be sufficient to ensure the wheels do not slide. The RBT (Running Brake Test) should be able to confirm that both requirements are met at that location. If the train does not decelerate at the demanded rate and adhesion is good then a brake system defect should be suspected. During the RBT, if the brake system is performing as required then the train will decelerate at the demanded rate (e.g. 6%) as long as the required adhesion is available at that particular location. This will confirm that the brake system is performing correctly and the driver can be confident that the train will decelerate at the demanded rate as long as the necessary adhesion is available, thereby eliminating one part of the risk of a SPAD or station overrun.

 

[choochoochoo]

Exactly. This is why it isn’t (or shouldn’t) be something you only ever do once at the start of a journey and then forget about.

Although if you're driving metro stopping patterns there is no need for constant RBTs

The pulling away from your last stop and the stopping you're doing at the next give you plenty indication of braking performance.

 

[whoosh]

Goodness me, what a thread!

At an educated guess, I expect it's all down to the suddenness of the braking, rather than the amount.

With a Meridian (class 222), and a class 387, you can end up unintentionally applying the brakes 'not very smoothly' i.e quite suddenly, if you grip the controller with your hand gripping horizontally.
With your hand gripping the controller vertically - gripping to the side of controller, you can control the movement into the braking position much better - more smoothly. You are better able to use your fingers to stop the advancing of the controller further into the braking position.


A class 800 looks to have it's controller only designed for use with the hand holding it horizontally - which would seem to direct it's use into a potentially less smooth technique.

 

[Atishyou]

Actually if drivers are driving poorly then yes that should be called out. Braking hard for adverse signals is absolutely fine, but it absolutely isn't when braking for stations and speed restrictions etc. As drivers we have to aim to provide the best overall journey experience possible , especially on longer distance journeys. Braking suddenly and heavily is not good way to drive and most DSMs will pull a driver up for that.

What about where speed restrictions aren't correctly placed?

E.g. sufficient distance hasn't been allowed for slowing down.

Is a harsh, nearly full service brake application suitable, or would you rather risk going over the ESR at a higher speed?

 

[DoubleO]

What about where speed restrictions aren't correctly placed?

E.g. sufficient distance hasn't been allowed for slowing down.

Is a harsh, nearly full service brake application suitable, or would you rather risk going over the ESR at a higher speed?

You would absolutely not risk going over an ESR at a higher speed. I would use as much brake as I felt necessary to achieve the ESR, and report to the signaller if I feel sufficient braking distance has not been provided.

 

[Atishyou]

You would absolutely not risk going over an ESR at a higher speed. I would use as much brake as I felt necessary to achieve the ESR, and report to the signaller if I feel sufficient braking distance has not been provided.

Fyi, I'm sure you'll know that in some instances where they've been placed incorrectly, no matter how much brake you use, even using emergency, you still can't get down to the speed shown.

 

[irish_rail]

Fyi, I'm sure you'll know that in some instances where they've been placed incorrectly, no matter how much brake you use, even using emergency, you still can't get down to the speed shown.

Yes, I'm aware that emergency speed restrictions are sometimes poorly placed, particularly at 125mph. And yes, I obviously brake hard in such circumstances. I'm calling out those who routinely brake like this, not everyone else who will brake hard only when necessary.

 

[niggill617@gma]

I don't believe this is the case. I think I'll have a look about today.

I pretty much never run my train at its maximum speed and due to the nature of working Metro, I don't run to linespeed either because I'm accelerating and then braking for the next station. I might touch linespeed but in the grand scheme of things I spend most of my time under it.

Considering that linespeed change. I don't carry out a brake test each time. So a quick running brake at 20mph to determine if I could safely stop at 20mph would be different to what's needed at 100mph.

With the obsession about calculating braking performance I think a significant factor has been omitted. Gravity will also have an effect. Braking on a gradient will be different if your going up or down a hill.

There is also factor or running brake tests for the prevailing conditions being almost worthless a few seconds later. If I carry out a running brake test at location X on a dry section of track then it rains 5 minutes later. Any braking I do will now be affected by the weather. Even in leaffall by the time you carry out your first running brake,. The next 100m down the line could be significantly different.

Knowing my train is braking at 6% still doesn't tell me if it's going to stop if I was going 10mph or 60mph

RBT from 20 mph is only significant re tread brakes, the coefficient of friction between block and wheel, increases slightly at lower speed. Disc brakes are even throughout the speed spectrum; low brakes force gives relatively low retarding force, higher brake force gives superior braking compared to tread brakes.

Regarding the calculation requirement of TDLCR, the gradient component is part of the general calculation. Railway gradients are elongated triangles when viewed in profile; thus 9.81 m/s/s divided by the gradient gives the correction. No need to go off on a tangent, remember: knowledge not a procedure, intuition first.

Braking in the wet does not necessarily increase stopping distance. Wet clean tribometer values range from 0.3 to 0.13 . The latter value will sustain a deceleration of about 1.27 m/s/s; hence modern traction will possess an emergency rate of 1.2 m/s/s, in the wet clean.

Wet dampened leaf has a value of 0.06 to 0.01, average being 0.05, this will mostly accommodate typical step 1or 2 braking. RAIB report Salisbury will surely explain the relationship of friction and stopping, or at least refer the reader to previously released information.

Aside. Just because I refer to psychometric tests as fancy, (elaborate in structure) doesn't mean I fail to appreciate the benefits.

 

[ComUtoR]

Regarding the calculation requirement of TDLCR, the gradient component is part of the general calculation. Railway gradients are elongated triangles when viewed in profile; thus 9.81 m/s/s divided by the gradient gives the correction.

When I'm driving, how do I check the gradient so that I can include it when trying to calculate my brake force ?